One of the questions refers to the so-called Cantril Ladder: "Please imagine a ladder, with steps numbered from 0 at the bottom to 10 at the top. The top of the ladder represents the best possible life for you and the bottom of the ladder represents the worst possible life for you. On which step of the ladder would you say you personally feel you stand at this time?"

Questions like those were balanced with other criteria like gross domestic product per capita, life expectancy, social support, trust in government and business, perceived freedom, and generosity.

Denmark ranked first for the third time. It was followed by Switzerland, Iceland, Norway, Finland, Canada, the Netherlands, New Zealand, Australia, and Sweden — nations that are notably homogenous, The New York Times explained.

All the way at the bottom of the list was Burundi, clustered alongside Syria, Togo, Afghanistan, Benin, Rwanda, Guinea, Liberia, Tanzania, and Madagascar. These unhappiest of countries have been racked by war, disease, and in many cases both.

As the BBC reported, "The report found that people are happier living in societies where there is less inequality of happiness. Likewise it found that the bigger the gap — or inequality — in a country's happiness, the more widespread unhappiness is as a whole."